Device for treating substrates

ABSTRACT

A device treats substrates with a liquid, which device has a conveying device by which the substrates can be conveyed in a conveying direction through a container containing a liquid. A weir that has an edge over which the substrates can run and which, at least in sections, extends obliquely relative to the conveying direction of the substrates. The weir is used in the device for treating substrates with a liquid. The weir has at least one edge which extends obliquely at least in sections.

The invention relates to a device according to the preamble of claim 1,and to a weir according to the preamble of claim 11.

In many fields, in particular in the semiconductor or more specificallythe solar cell industry, treatments of substrates, in particular ofwafers, which relate to only one side of the substrate are necessary forvarious applications. In the case of such unilateral processes, thatside of the substrate that is opposite the side to be treated shouldusually not be affected by the treatment. In the field of wet processes,edge insulation by wet chemistry (unilateral etching of the parasiticemitter that has been applied to the reverse side by diffusion),polishing (chemical smoothing of the textured front or reverse side ofthe substrate, respectively), galvanic processes such as theelectrochemical deposition of a metal coating, or unilateralpreconditioning steps prior to other treatments such as hydrophobizingof the substrate edges, are to be mentioned in an exemplary mannerherein.

As opposed to batch methods which as a matter of the system relate toboth sides of the substrate, unilateral treatments are implementable invarious ways in inline methods. In the case of a method for this purposethat is known from EP 1 733 418 B1, full contact of the substrate on thelower side with a treatment liquid is established while configuring of aso-called meniscus. In the case of another known method, unilateralcontact between the substrate and the treatment liquid is established byway of structured rollers which transport the treatment liquid up to thelower side of the substrate.

Reference is made to substrates hereabove and hereunder. These alsoinclude semiconductor substrates, in particular wafers such as siliconwafers. Solar cell wafers are understood to be wafers that are destinedfor the production of solar cells.

The aforementioned method for establishing full contact on the lowerside between the substrate and the treatment liquid while configuring ameniscus has a number of advantages for the treatment of substrates witha liquid, in particular for unilateral inline processes based on wetchemistry. Apart from a uniform treatment of the lower side of thesubstrate and from the fully planar thermal contact of the substratewith the surface of the treatment liquid, which usually results inimproved process control, by way of the permanent contact of thesubstrate the use of treatment liquids having a lower concentration ispossible than in the case of the treatment liquid being applied byroller to the lower side (same process distance, but longer processingtime). Apart from the lower cost of chemicals, this also reduces apotentially aggressive gaseous phase on the upper side of the substrate.Also, in comparison the complexity in terms of apparatus issignificantly lower.

However, the principle of full contact of the substrate on the lowerside while configuring a meniscus can also have inherent disadvantages.One potential disadvantage lies in that when the meniscus is being tornoff, this usually taking place when exiting a container containing thetreatment liquid above an exit weir, a liquid lamella, caused by thesurface tension of the treatment liquid between the substrate and thesurface of the bath, is defined, said liquid lamella tearing when thesubstrate is transported onward. The main direction of elongation of thelamella herein usually points in the travelling direction of thesubstrate, which can also be referred to as the transportation directionof said substrate. In the case of such a tear-off, droplets of thetreatment liquid are often propelled onto the upper side of thesubstrate. The intensity of this undesirable effect depends on thesurface tension of the treatment liquid, the viscosity of the latter,and on the process management (ratio of filling level of the bath or thecontainer, respectively, to the weir height, and/or the recirculationflow that results therefrom).

In order to address issues that arise from splashes of this type, it maybe considered that the properties of the liquid be modified, for exampleby adding of materials that change the viscosity. However, this is notalways possible or desirable, or is associated with other issues. Also,the upper side of the substrate can by protected from the effect ofthese splashes by one or a plurality of protective layers. However, asignificant complexity in terms of the method is often associatedtherewith, or this procedure is not or only poorly compatible with theother aspects of the process management.

Against this background, the present invention is based on the object ofproviding a device which enables splashes of the type described on theupper side of the substrate to be reduced.

This object is achieved by a device having the features of claim 1.

The invention is furthermore based on the object of providing a weirwhich enables splashes of the aforementioned type to be reduced.

This object is achieved by a weir having the features of claim 11.

The invention is furthermore based on the object of providing a methodby means of which the formation of splashes can be reduced when a liquidlamella is being detached from a substrate edge.

This object is achieved by a method having the features of thealternative independent claim.

Advantageous refinements are the respective subject matter of dependentclaims.

The device according to the invention for treating substrates with aliquid has a transportation device, by means of which the substrates aretransportable in a transportation direction through a container thatcontains the liquid, and a weir having an edge that is navigable by thesubstrates and at least in portions runs obliquely to the transportationdirection of the substrates.

The invention is based on the concept that the aforedescribed splashesarise above all when the edge of the weir that is navigable by thesubstrates runs orthogonally to the transportation direction of thesubstrates. This is because the mechanical force that acts on the liquidlamella that is configured between the liquid and the substrate rearedge when the substrates are being transported onward is at maximum inthis case. Once the stress limit of the liquid lamella is exceeded, thelatter at a geometrically unspecified point begins to rupture, andsplashes can be propelled onto the upper side of the substrate or ontothe upper side of subsequent substrates.

However, if that edge of the weir that is navigable by the substrates isat least in portions configured so as to be oblique to thetransportation direction of the substrates, the load that in the courseof the substrate being moved onward acts on the liquid lamella is atmaximum at that corner of the substrate rear edge that first navigatesthe edge, such a retraction of the liquid lamella commences at thiscorner. As a consequence, a retraction front of the liquid lamella isconfigured. If the substrate is transported onward in the transportationdirection, this retraction front runs to an opposite corner of thesubstrate rear edge. The influence of force on the liquid lamella can bereduced in this way. The liquid lamella is pretensioned to a lesserextent. “Soft” tearing off is initiated by the retraction front thatruns from one corner of the substrate rear edge to the other corner,said retraction front simultaneously representing a tear-off front. As aconsequence, splashes onto that upper side of the substrate or of asubsequent substrate that is not to be treated can be avoided or atleast reduced.

The aforedescribed effect can also be achieved by way of an obliquealignment of the substrates in relation to the navigable edge of theweir, or by placing the substrates onto the transportation device in arotated manner. However, in practice this is disadvantageous for aplurality of reasons:

On the one hand, placing the substrates in such a rotated manner is notpossible with all commonly used handling systems. Rather, commonly usedhandling systems are adapted for the substrates to be placed onto thetransportation device by way of one substrate side being parallel withthe transportation direction. Those systems that in principle permitrotated placing would have to be adapted, in particular instructed, tothis end in a complex manner.

On the other hand, substrates that have been placed in such a rotatedmanner can be centered on a transportation track only with difficultyand by way of complex means. In the case of the substrates being rotatedmanually on the transportation device, reproducible rotated positioningwithout aids is achievable only with great difficulty. Moreover,practice has demonstrated that rotated placing of the substrates can beassociated with increased breakages and consequently higher costs.

Not least, by placing the substrates in a rotated manner, the effectivelength and width of the substrates and with this the required passageclearance and passage length are increased, this making the device moreexpensive at the same throughput.

By virtue of these disadvantages, the substrates by means of thetransportation device are advantageously transported in such a mannerthat two edges of the substrate run so as to be parallel with thetransportation direction, wherein the weir however has the edge designedaccording to the invention, which at least in portions runs obliquely tothe transportation direction of the substrates.

In one advantageous design embodiment, the edge extends across at leasttwo transportation tracks and therebetween has an inconsistent edgeprofile. A transportation track in the context of the present inventionis to be understood to be a motion track of the substrates on which thesubstrates by means of the transportation device are transportablethrough the container that contains the liquid. In as far as mention ismade in this application of transportation of the substrates “through”the container that contains the liquid, the term “through” is to beunderstood in a very wide context. It thus depends on the specificdesign embodiment of the transportation device whether the substratesare transported literally through the container or rather across the topof the container. For example, the substrates by means of transportationrollers are first transported across a container wall, before beingtransported in the container at a level that is below an upper edge ofthe container wall through the container, the lower sides of saidsubstrates thereby being brought into contact with the liquid. In thisexemplary case, the substrates are transported literally through thecontainer. In particular, the surface of the liquid in this containercan be lower than the upper edge of the container wall. In anothervariant of design, the surface of the liquid in the container can behigher than the upper edge of the container wall. As a consequence,liquid runs across the container wall and is collected in an overflowcontainer, for example, and returned to the container. In this case, thesubstrates when being transported do not have to be lifted across thecontainer wall but can be transported across the container wall and thecontainer having the liquid therein at the same height as outside thecontainer, specifically in such a manner that the lower sides of thesubstrates are brought into contact with the liquid as said lower sidesare being transported across the container. In the case of this variantof design, many observers would possibly tend not to refer to thetransportation of the substrates “through” the container, but insteadrefer to transportation of the substrates across the container. However,in the context of the present application and of the present invention,this variant of design and embodiments with an equivalent effect arealso comprised by the term “through”, such that transportation of thesubstrates through the container is present therein.

The at least two transportation tracks are preferably aligned so as tobe mutually parallel such that a plurality of rows of substrates aresimultaneously transportable beside one another through the containerthat contains the liquid.

A width of the transportation track is presently to be understood to bea maximum width of the substrates that are transported in thistransportation track. This width of the transported substrates extendsperpendicularly to the transportation direction. In the context of thepresent invention, a region is located between two transportation trackswhen said region is not covered by at least one transportation track. Inpractice, the transportation track can be chosen to be wider in order tobe able to take into account variations in the substrate dimensions orinaccuracies in positioning the substrates on the transportation device.

An inconsistent edge profile in the context of the present invention isunderstood to be an edge profile which has at least one step in thedirection of the transportation direction or in the opposite direction.

The inconsistent edge profile is advantageously configured in such amanner that said inconsistent edge profile has a step between two of theat least two transportation tracks. In the case of the edge extendingacross more than two transportation tracks, it is advantageous when theedge profile has a step between each of the transportation tracks. Anedge profile of this type advantageously configures a sawtooth profile.

Such an inconsistent edge profile is readily producible, for example byjoining a plurality of weir or edge elements, respectively, that run ina straight line and are therefore producible with little complexity.

According to one preferred refinement, the edge extends across at leasttwo transportation tracks and therebetween has a consistent edgeprofile.

In the context of the present invention, an edge profile is consistentwhen the latter in the transportation direction and in the oppositedirection does not have any step. The consistent edge profileadvantageously runs in the form of a triangular profile across thetransportation tracks such that a kink is in each case disposed betweenthe transportation tracks. In this way, as compared to a weir having aninconsistent edge profile between the transportation tracks, a reducedinvestment in material and thus a less complex production can beachieved.

In one advantageous embodiment, the edge has an edge profile that in themathematical sense is differentiable at each point. The edge profile canadvantageously be configured so as to be sinusoidal. It is alsoconceivable for the edge profile to be configured as an arbitrary curveor according to a polynomial function. It has been demonstrated inpractice that a particularly gentle tear-off of the liquid lamella fromthe substrates and consequently an even greater reduction of splashesonto the substrate upper side can be achieved by way of an edge profileof this type.

In order for a particularly large angle of inclination of that edge thatis navigable by the substrates to be obtained within one transportationtrack, it is advantageous when the edge within this transportation trackhas an inconsistent edge profile. The stress on the liquid lamella onthe substrate rear edge can be further reduced by way of the angle ofinclination that is maximized in this manner within the transportationtrack, and on account thereof an even softer tear-off can be achieved,and ultimately the quantity of the liquid that is unintentionallysplashed onto the substrate upper side can be further reduced.

In one further design embodiment, the edge at least in portions has arounded, preferably a sinusoidal, edge profile. The tear-off behavior ofthe liquid film can advantageously be influenced by way of a respectiveadaptation of the rounded profile, while considering further processparameters such as, for example, the viscosity of the fluid, or thelike.

In terms of a simplified assembly of the weir in the device it can beadvantageous when the edge extends across more than two transportationtracks, preferably across at least three transportation tracks, andparticularly preferably across all transportation tracks. Additionalassembly complexity for the assembly of individual weirs or edgeelements per transportation track can be avoided in this manner.

Transportation of the substrates that is particularly favorable in termsof complexity and gentle on the material can be achieved when the devicehas transportation rollers that in the transportation direction aredisposed ahead of and behind the weir and by means of which thesubstrates are transportable through the container that contains theliquid.

In one advantageous design embodiment, the edge in the transportationdirection extends across at least 50%, of an available spacing of thetransportation roller that when viewed in the transportation directionis disposed as the last one ahead of the weir. It has been demonstratedin practice that an already sufficiently large angle of inclination ofthe edges and consequently an effective avoidance of splashes onto thesubstrate upper side can be achieved in this manner. In order for theangle of inclination of the edge in relation to the transportationdirection between two transportation rollers to be further increased, itis advantageous for the edge in the transportation direction to extendacross at least 75% and particularly preferably across at least 95% ofthe available spacing described.

In the case of individual applications it may be necessary for thetransportation rollers to be disposed ahead of and behind the weir atsuch a minor spacing that a sufficiently oblique edge profile is nolonger possible in the case of the weir being disposed between thetransportation rollers. In such cases, it is advantageous for therotation axle of at least one of the transportation rollers to penetratethe weir. It can be achieved in such a manner that the edge of the weir,despite the minor spacing of the transportation rollers, can be embodiedin a sufficiently oblique manner such that splashes onto the substrateupper side can be avoided.

The device according to the invention can be advantageously used fortreating the lower sides of substrates, preferably solar cell wafers, bywet chemistry by way of a liquid. The substrate lower sides herein arepreferably brought into contact with the liquid that is disposed in acontainer in such a manner that a meniscus is configured between theliquid surface in the container and the substrates.

A weir for use in a device for treating substrates with a liquid isfurther a subject matter of the invention. The weir according to theinvention has an edge that runs obliquely at least in portions.

Protruding portions of the edge that protrude so as to be substantiallyperpendicular to the main direction of extent of the weir are presentlyreferred to as protrusions of the weir, or as protrusions of the edge ofthe weir, respectively. In an analogous manner, the weir or edgeportions that are recessed in the opposite direction are referred topresently as recesses of the weir, or of the edge of the weir,respectively. In one advantageous refinement, the edge has at least oneprotrusion or at least one recess, preferably a protrusion.

In one preferred embodiment, the edge at least in portions has asawtooth profile. The protrusions and/or recesses of the edge thatconfigure the sawtooth profile herein run so as to be substantiallyperpendicular to the main direction of extent of the weir.

Depending on the specific process parameters at which the weir is to beemployed in the device, it can moreover be advantageous for the edge atleast in portions to have a triangular profile and/or an undulatedprofile.

With a view to a uniform outflow of the liquid from the edge of the weirit is advantageous for the edge to have an in particular undulatedvertical profile. A vertical profile is presently understood to be aprofile of the edge of the weir that extends perpendicularly to the edgeprofile that is oblique at least in portions.

The weir is preferably made so as to be integral, in particular by wayof subtraction of material from an integral primary body, for example bymilling. It has been demonstrated in practice that improved dimensionalaccuracy (linearity) of the weir edges can be guaranteed in this way.Moreover, the weir can be produced by fewer operational steps. Thisholds true in particular in comparison to an alternative productionmethod for the weir, in which the shape of the edge is implemented byfolding in a plastics plate and subsequent fixing of the latter by meansof welding. The aforementioned advantages also result in comparison to aproduction of the weir by way of individual plates that areretroactively connected. It has moreover been demonstrated in practicethat in the case of the described production of the weir by means ofmaterial subtraction, in particular by means of milling, suitablefastening elements on the lower side of the weir can be formed at lowinvestment. These fastening means allow reliable and simple fastening ofthe weir to the associated device.

In one further embodiment, the weir has at least one opening forreceiving an axle. In as far as the device in which the weir is to beused disposes of transportation rollers for transporting the substrates,the axle of at least one of these transportation rollers can be receivedin the at least one opening of the weir. The weir advantageously has asealing element that is disposed in the at least one opening.

The invention is moreover directed toward the use of a weir according tothe invention in a device according to the invention.

The method according to the invention for detaching a liquid lamellafrom a substrate edge provides that a tear-off front is configured at atleast one point of the liquid. This tear-off front is guided along thesubstrate edge and a width of the liquid lamella (20) is reduced in thisway. The width of the liquid lamella herein is to be understood as theextent of the latter substantially parallel with the substrate edge. Ashas been described above, the influence of force on the liquid lamellacan be reduced by reducing the width of the liquid lamella before thelatter is torn off the substrate edge, and the risk of the formation ofsplashes can be reduced in this way.

The width of the liquid lamella prior to the liquid lamella being tornoff the substrate edge, as compared to the original width thereof, ispreferably reduced by at least 50%, preferably by at least 80%, andparticularly preferably by at least 97%. The risk of the formation ofsplashes can be increasingly reduced and at best completely avoided inthis way.

In one preferred variant, the tear-off front is configured at a cornerof the substrate edge. This has proven successful in practice.

The tear-off front is advantageously guided up to a corner of thesubstrate edge. This enables a simple and reliable method management.

The invention will be furthermore explained in more detail by means offigures. In as far as expedient, elements with equivalent functions areprovided with the same reference signs. The invention is not limited tothe exemplary embodiments that are illustrated in the figures, this alsoapplying to functional features. The description up to this point aswell the description of the figures hereunder include numerous featureswhich in the dependent subclaims are to some extent reflected so as tocombined with one another. However, a person skilled in the art willconsider these features as well as all other features that are disclosedabove and hereunder in the description of the figures individually andcombine these features to form further purposeful combinations. Inparticular, these features are in each case combinable individually andin any suitable arbitrary combination with the device and the weir ofthe respective independent claim.

In the figures:

FIG. 1 shows schematic illustrations of a fragmented lateral view of adevice according to the prior art in a first (a), a second (b), and athird (c) state;

FIG. 2 shows an in-principle illustration for highlighting theconfiguration of a liquid lamella between a substrate rear edge and aweir having a linear edge according to the prior art;

FIG. 3 shows a first exemplary embodiment of a device and of a weirhaving an edge that runs obliquely at least in portions, in a schematicillustration;

FIG. 4 shows an in-principle illustration for highlighting theconfiguration of a liquid film in the case of an edge that runsobliquely at least in portions, in a first (a) and a second (b) state,and an exemplary embodiment of the method according to the invention;

FIG. 5 shows a schematic illustration of a refinement of the deviceaccording to FIG. 3;

FIG. 6 shows a schematic illustration of a further embodiment of thedevice according to FIG. 3;

FIG. 7 shows a schematic illustration of a further design embodiment ofthe device according to FIG. 3;

FIG. 8 shows a schematic illustration of a refinement of the deviceaccording to FIG. 3;

FIG. 9 shows a fragmented lateral view of the illustration according toFIG. 8;

FIG. 10 shows a schematic illustration of a perspective view of a weir.

FIG. 1 shows a device 2 for treating substrates with a liquid 4,according to the prior art, in a first (a), a second (b), and a third(c) state. The device 2 is illustrated in a sectional illustration and,for reasons of clarity of the drawing, only in a fragmented manner, thatis to say with the omission of further elements of the device 2. Thedevice 2 has a container 6 that contains the liquid 4 and isunilaterally delimited by means of a weir 8. The weir 8 is configuredfor preventing, or limiting, respectively, a discharge of the liquid 4from the container 6. Moreover, the weir 8 has a straight edge 10 thatis navigable by substrates 14. Transportation rollers 12 by means ofwhich substrates are transportable across the liquid 4, or across theedge 10 of the weir 8, respectively, are disposed on either side of theweir 8.

Such a state of transportation is schematically illustrated in FIG.1(b). The latter shows how the substrate 14, while configuring alower-side liquid film 16, by means of the transportation rollers 12 istransported across the weir 8 and the edge 10 of the latter along atransportation direction 18. As can be seen in FIG. 1(c), caused by thesurface tension of the liquid 4, a liquid lamella 20 is configured onthe read edge 22 of the substrate 14 when the substrate 14 is beingtransported onward. Said liquid lamella 20 is not immediately torn offbut is elongated when the straight edge 10 is navigated.

FIG. 2 shows an in-principle illustration for highlighting theconfiguration of this liquid lamella 20 between the substrate rear edge22 and the weir 8, or the straight edge 10, respectively. The view ofFIG. 2 herein corresponds to a plan view of the state illustrated inFIG. 1 (c), wherein for reasons of clarity a few elements of the device24 are not illustrated. When the substrate 14 is being transportedonward along the transportation direction 18, further elongation of theliquid lamella 20 takes place until the stress limit of the latter isexceeded, and consequently tearing-off of the liquid lamella 20 from thesubstrate rear edge 22 arises. A substantially homogeneous elongation ofthe liquid lamella 20 along the transportation direction 18 isestablished by way of the straight profile of the edge 10 of the weir 8in relation to the transportation direction 18. In simple words, thereexists no point along the liquid lamella 20 that has a pronouncedsuperelevation in terms of tension. The tear-off of the liquid lamella20 thus takes place so as to proceed from a geometrically notunequivocally established point. In the case of a tear-off of the liquidlamella 20 that is undefined in such a manner, a formation of splashesin which liquid 4 is unintentionally propelled onto the upper side ofthe substrate 14 or of subsequent substrates in the process oftenarises.

FIG. 3 shows a schematic illustration of a device 24 for treatingsubstrates 14 with a liquid 4. The device 24 has a transportation device26 by means of which the substrates 14 are transportable through acontainer 28 that contains the liquid 4. The device 24 moreover has aweir 30 having an edge 32 that is navigable by the substrates 14, saidedge 32 at least in portions running obliquely to the transportationdirection 18 of the substrates 14.

The transportation device 26 has transportation rollers 34 that in thetransportation direction 18 are disposed ahead of and behind the weir 30and by means of which the substrates, or the substrate 14, respectively,are/is transportable through the container 28 that contains the liquid4.

In the present exemplary embodiment, the maximum extent E of the edge 32in the transportation direction 18 is at least 95 percent of the spacingA of the transportation rollers 34 which in the transportation direction18 are disposed directly ahead of and behind the weir 30.

The substrate in FIG. 3 is illustrated with dashed lines, since saidsubstrate is not a component part of the device 24. By way of thebearing of the individual substrate 14 on the transportation rollers 34as is illustrated in the present case, a single transportation track 36is configured along the transportation direction 18, the substrate 14moving along said transportation track 36 through the container 28 thatcontains the liquid 4. The illustration of FIG. 3 is limited to merelyone transportation track 36, wherein further transportation tracks 36can be configured by having a plurality of substrates 14 that aresmaller and/or narrower bearing thereon, for example, and/or by usingwider transportation rollers. The device 24 can fundamentally also havea plurality of transportation devices 26 or transportation rollers 34,respectively, that are disposed beside one another, such that onetransportation track 36 can be configured along each one of the rows oftransportation rollers that lie beside one another.

FIG. 4 shows an in-principle illustration for highlighting the tear-offof a liquid lamella 38 from the substrate rear edge 22 when navigatingthe edge 32 of the weir 30 that runs obliquely to the transportationdirection 18, in a first (a) and a second (b) state. FIG. 4 in this waysimultaneously illustrates an exemplary embodiment of the methodaccording to the invention. As has already been highlighted in thecontext of the in-principle illustration in FIG. 2, the liquid lamella20 when navigating the edge 32 is first elongated along thetransportation direction 18 and mechanically stressed. Since the edge 32of the weir 30 runs obliquely to the transportation direction 18, theliquid lamella 38 is initially imparted the maximum mechanical stress ata lower left corner 23 a of the substrate 14, or at the corner 23 a ofthe substrate edge 22, respectively. As is illustrated by FIG. 2(b), atear-off front 39 is configured at this point, and emanating from thispoint, a retraction of the liquid lamella 38 in the direction of theright lower corner 23 b of the substrate 14 commences. The tear-offfront 39 is guided along the substrate edge 22, and a width of theliquid lamella 38 is reduced in this way. As a result of the obliqueprofile of the edge 32, the tear-off front 39 is guided up to the corner23 b of the substrate edge 22, and a targeted tear-off of the liquidlamella 38 is achieved at said corner 23 b, in which tear-off theformation of splashes and the unintentional application of liquid 4 ontothe upper side of the substrate 14 can be avoided.

FIG. 5 shows a further device 24 a in which three transportation tracks36 for the substrates 14 are configured, said three transportationtracks 36 running so as to be mutually parallel and along thetransportation direction 18. The device 24 a otherwise differs from thedevice 24 substantially in terms of the design of the weir and of theedge of the latter, such that the further elements of the device 24 aare not illustrated in FIG. 5.

The weir 40 that is used in the exemplary embodiment of FIG. 5 has anedge 44 which extends across at least two of the transportation tracks36 and therebetween has an inconsistent edge profile 42. The edgeprofile 42 along the transportation direction 18 has a plurality ofprotrusions 46. Alternatively, the latter can fundamentally also beembodied as recesses. The protrusions 46 extend substantially in adirection that runs perpendicularly to a main direction of extent 48 ofthe weir. Accordingly, the edge 44 has a sawtooth profile 50. In orderfor the angle of inclination within a transportation track to be furthermaximized, the edge 44 within the right transportation track 36 has aninconsistent edge profile having a plurality of protrusions 46.

FIG. 6 shows a further device 24 b having a weir 52 which has an edge54. The edge 54 extends across three transportation tracks 36 andtherebetween has a consistent edge profile 56. As for the illustrationof further elements of the device 24 b in terms of the drawing, theexplanations pertaining to FIG. 5 apply in an analogous manner.

A further device 24 c is illustrated in FIG. 7. Said device 24 c has aweir 58 having an edge 60 which in turn extends across threetransportation tracks 36. The edge 60 presently has an edge profile 62that is differentiatable at each point. The edge profile 62 has neithersteps nor kinks. The edge 60 is rounded and presently has a sinusoidaledge profile. As for the illustration of further elements of the device24 c in terms of the drawing, the explanations pertaining to FIG. 5apply in an analogous manner.

Depending on the case of application, it is also possible for one andthe same edge to have a portion-by-portion combination of the edgeprofiles 42, 56 and 62 that are included in the exemplary embodimentsaccording to FIGS. 5, 6, and 7. In other words, one and the same weircan have an edge having an edge profile that portion-by-portion isconsistent, inconsistent, and/or differentiatable.

FIG. 8 shows a schematic illustration of a further device 24 d. Thedevice 24 d has a weir 64 which is penetrated by a rotation axle 66 ofone of the transportation rollers 34. The weir 64 for this purpose hasan opening 68 for receiving the axle 66. FIG. 9 shows a fragmentedlateral view of the illustration of FIG. 8, and highlights thearrangement of the opening 68 for receiving the axle 66 of thetransportation roller 34.

FIG. 10 shows a schematic illustration of a perspective view of a weir70 for use in a device according to one of the preceding exemplaryembodiments. The weir 70 is presently produced by means of subtractionof material, specifically by milling, from a primary body 72 which isillustrated with dashed lines. The weir 70 has an edge 74 which inportions has an undulated vertical profile 76. The vertical profile 76can preferably be configured along the entire edge 74 of the weir 70,wherein for reasons of improved clarity of illustration only a profileof the vertical profile in portions is presently illustrated.

LIST OF REFERENCE SIGNS

-   2 Device according to the prior art-   4 Liquid-   6 Container-   8 Weir-   10 Straight edge-   12 Transportation rollers-   14 Substrate-   16 Liquid film-   18 Transportation direction-   20 Liquid lamella-   22 Substrate rear edge-   23 a, 23 b Corner-   24, 24 a-d Device-   26 Transportation device-   28 Container-   30 Weir-   32 Oblique edge-   34 Transportation rollers-   36 Transportation track-   38 Liquid lamella-   39 Tear-off front-   40 Weir-   42 Inconsistent edge profile-   44 Inconsistent edge-   46 Protrusion-   48 Main direction of extent-   50 Sawtooth profile-   52 Weir-   54 Consistent edge-   56 edge profile-   58 Weir-   60 Edge-   62 Edge profile-   64 Weir-   66 Rotation axle-   68 Opening-   70 Weir-   72 Primary body-   74 Edge-   76 Vertical profile-   A Spacing-   E Extent

1-21. (canceled)
 22. A device for treating substrates with a liquid, thedevice comprising: a container containing the liquid; a transportationdevice by which the substrates are transportable in a transportationdirection through said container; and a weir having an edge beingnavigable by the substrates and at least in portions runs obliquely tothe transportation direction of the substrates.
 23. The device accordingclaim 22, wherein said edge extends across at least two transportationtracks and there-between has an inconsistent edge profile.
 24. Thedevice according to claim 22, wherein said edge extends across at leasttwo transportation tracks and there-between has a consistent edgeprofile.
 25. The device according to claim 22, wherein said edge has anedge profile that is differentiable at each point.
 26. The deviceaccording to claim 22, wherein said edge within at least onetransportation track has an inconsistent edge profile.
 27. The deviceaccording to claim 22, wherein said edge at least in portions has arounded edge profile.
 28. The device according to claim 22, wherein saidedge extends across more than two transportation tracks.
 29. The deviceaccording to claim 22, wherein said transportation device hastransportation rollers that in the transportation direction are disposedahead of and behind said weir and by means of said transportationrollers the substrates are transportable through said container thatcontains the liquid.
 30. The device according to claim 29, wherein saidedge extends across at least 50% of an available spacing of a first ofsaid transportation rollers that when viewed in the transportationdirection is disposed as a last one ahead of said weir from a second ofsaid transportation rollers that when viewed in the transportationdirection is disposed as a first one behind said weir.
 31. The deviceaccording to claim 29, wherein said transportation rollers each have arotation axle and said rotation axle of at least one of saidtransportation rollers penetrates said weir.
 32. A weir for use in adevice for treating substrates with a liquid, the weir comprising: abody having an edge running obliquely at least in portions.
 33. The weiraccording to claim 32, wherein said edge has at least one protrusion orat least one recess formed therein.
 34. The weir according to claim 32,wherein said edge at least in portions has a sawtooth profile.
 35. Theweir according to claim 32, wherein said edge has a non-planar,undulated, vertical profile.
 36. The weir according to claim 32, whereinthe weir is embodied so as to be integral, produce by way of subtractionof material from a primary body.
 37. The weir according to claim 32,wherein said body has at least one opening formed therein for receivingan axle.
 38. A method for detaching a liquid lamella from a substrateedge, which comprises the steps of: configuring a tear-off front at atleast one point of the liquid lamella; and guiding the tear-off frontalong the substrate edge and a width of the liquid lamella being reducedin this way.
 39. The method according to claim 38, wherein the width ofthe liquid lamella prior to the liquid lamella being torn off thesubstrate edge, as compared to an original width of the liquid lamella,is reduced by at least 50%.
 40. The method according to claim 38,wherein the tear-off front is configured at a corner of the substrateedge.
 41. The method according to claim 38, wherein the tear-off frontis guided up to a corner of the substrate edge.